Moisture accumulation against the inner face of goggle lens resulting from the wearer's perspiration and breathing can result in the formation of vision-impairing beads which are a great inconvenience to skiers, motorcyclists, paintball game players and the practitioners of similar demanding sports activities. Fogging inside goggles can be reduced by multi-layered lenses and reflective coating as disclosed in U.S. Pat. No. 5,018,223 Dawson et al. The inner face of the goggle lens can also be coated with an hydrophilic composition which lowers the surface tension of water droplets causing them to spread rather than form vision-impairing beads. Polyester films coated with such a composition as the one disclosed in U.S. Pat. No. 4,467,073 are provided with sticky backing so that they can be glued against the inner surface of the goggle's lens. Sheets of such films are commercially available under the mark VISTEX from FILM SPECIALITIES, INC. of Whitehouse, N.J.
Since the exposed, coated surface of such a film is less resistant to abrasion than the material used in the fabrication of the goggle lens, the useful life of the goggle tends to be reduced due to early scratching of the film surface. Replacement of the anti-fogging film is impractical, and often yields less than desirable results due to the fact that part of the adhesive of the removed film tends to remain against the inner face of the lens. In practice, the entire lens and anti-fogging film assembly has to be replaced.
When the goggles are used in a highly moisture-laden environment, or when worn by subjects prone to a high level of perspiration, the entire fogging film tends to saturate with moisture and loses it anti-fogging properties. Unless the goggles provides for quick replacement of the lens assembly, the user is forced to replace the blurred goggles with a new set.
It would be advantageous to be able to quickly replace the saturated anti-fogging film in the middle of a sporting activity.